A lower scaling four-component relativistic coupled cluster method based on natural spinors

Abstract

We present the theory, implementation, and benchmark results for a frozen natural spinors-based lower scaling four-component relativistic coupled cluster method. The natural spinors are obtained by diagonalizing the one-body reduced density matrix from a relativistic MP2 calculation based on four-component Dirac-Coulomb Hamiltonian. The correlation energy in the coupled cluster method converges more rapidly with respect to the size of the virtual space in the frozen natural spinor basis than that observed in the standard canonical spinors obtained from the Dirac-Hartree-Fock calculation. The convergence of properties is not smooth in the frozen natural spinor basis. However, the inclusion of the perturbative correction smoothens the convergence of the properties with respect to the size of the virtual space in the frozen natural spinor basis and greatly reduces the truncation errors for both energy and properties calculations. The accuracy of the frozen natural spinor based coupled cluster methods can be controlled by a single threshold and is a black box to use.

31 pages , 8 figures

References in corpus (2)

• Relativistic equation-of-motion coupled-cluster method for the ionization problem: Application to molecules
• Implementation of Z-vector method in the relativistic coupled cluster framework to calculate first order energy derivatives: Application to SrF molecule

Cited by in corpus (4)

• Assessing MP2 frozen natural orbitals in relativistic correlated electronic structure calculations
• Applications of a perturbation-aware local correlation method to coupled cluster linear response properties
• Relativistic atomic structure calculations in support of spectroscopy
• A low-cost four-component relativistic coupled cluster linear response theory based on perturbation sensitive natural spinors